CYTOLOGICAL INDICATION OF THE INVOLVEMENT OF CALCIUM AND CALCIUM-RELATED PROTEINS IN THE EARLY RESPONSES OF BRYONIA-DIOICA TO MECHANICAL STIMULUS

The distribution of membrane-bound calium, activated calmodulin, and c allose synthesis was visualized in Bryonia dioica internodes before an d after mechanical stimulus, using fluorescent probes, respectively, c hlorotetracycline, fluphenazine, and aniline blue. Bright chlorotetrac ycline fluorescence remains localized in the plasma membrane of contro l cells, 30 s after stimulation calcium left the plasmaremma. A deloca lization of activated calmodulin was observed after wounding and depos ition of callose, which could not be detected before, appeared in the same times in most cells. The callose formation and the decrease in me mbrane-associated calcium suggest a rapid influx of calcium in the cyt osol and an intervention of this ion in the cascade of the early event s underlying Bryonia dioica thigmomorphogenesis.